The World Wide Web (“web”) contains a vast amount of information. Search engines assist users in locating desired portions of this information by cataloging web documents. Typically, in response to a user's request, a search engine returns links to documents relevant to the request.
Search engines may base their determination of the user's interest on a search query provided by the user. A search query is a request for information, where the request may specify one or more search terms. The goal of a search engine is to identify links to relevant search results based on the search query. Typically, the search engine accomplishes this by matching the terms in the search query to a corpus of pre-stored web documents. Web documents that contain the user's search terms are considered “hits” and are returned to the user.
The quality of the documents returned to the user depend on the quality of the ranking process used to rank the search results. For example, some ranking processes rank documents based on the number of links pointing to them, the ranks of the documents pointing to them, or the anchor text associated with the links pointing to them.
The categorization of documents is known. For example, in the context of web pages, one may categorize a web page known to be about a Japanese restaurant to a “Restaurant-Japanese”category. A user searching for a Japanese restaurant can select this category to aid the search. Currently, the categorization of documents is not particularly useful to search engines.